The present invention relates to an adjustable propeller system for an inboard/outboard motor in which the depth of the propeller and the angle of the propeller relative to the surface of the water are independently adjustable.
In order to maximize power during startup, the propeller of a power boat is preferably immersed more deeply in the water. On the other hand, during high speed operation, the propeller is preferably near the surface of the water. Commercially available connections for inboard/outboard motors have not provided this adjustability. As a result, current inboard/outboard motors are not able to maximize both power during start-up and during high-speed operation.
Due to the lack of adjustability, the current boat operators have gone to extreme measures to provide adjustment. During a turn, current power boats have opened a ballast tank in the front of the boat to fill it with water while simultaneously adjusting the trim angle of the propeller inward, i.e., pivoting the propeller towards the boat. This has allowed some depth adjustment. After the turn, it is necessary to re-adjust the trim angle and empty the water from the ballast tank. This complex operation would not be necessary if the depth of the propeller could be adjusted.
Some prior devices have provided the ability to adjust the depth of the outboard drive portion of an inboard/outboard motor. The prior depth adjustment devices have not been suitable for high-power applications because of insufficiently durable connections between the transom and the outboard drive portion and because the extended drive shaft portion between the transom and the outboard drive portion has not been supported sufficiently to withstand the high power.